Chromium coordination complexes



United States Paten'tF'O 2,909,545 CHROMIUlVI .COORDINATION COMPLEXES William S. Barnhart, Cranford, N. J., assignor, by mesne gassignment's, tOfMillIlGSOtH Mining and Manufacturing Company,-St.--Paul,-Minn, i2 corporation of Delaware N Drawing. Application March '11, 1955 Serial N0.-493,820

7 Claims. (Cl- 260-438) atoms with trivalent chromium compounds which are at least one third basic. Chromium compounds of .type are, for example, chromyl chloride, which is a hexavalent chromium compound which is reduced by an alcohol or other, reducing agent during the complex-forming repound, and it is this latter compound that forms the complex. Other chromium compounds which may be used are those which are initially in the trivalent state, such as chrornic chloride, chromic bromide, chromic nitrate, and chrornic acetate, these compounds being partially hydrolyzed in the presence of the 'perchlorofluoromonocarboxylic acid. In any event, the chromium compound entering the complex must contain at least one hydroxyl group.

When using the complexes as waterproofingtagents, the chromyl'halogen must be hydrolyzed just prior toor during application of the complexes to surfaces whichit is desired torender water. repellent. The hydrolyzed group Cr-OH 'polymerizes on .standing for a period of 4 to 12 hours at room temperature or upon heating at a .temperature. of 50 to 100 C.:for a period .ofone' hour. In thisnusethe pH of the final aqueous solution'should be between about 3 and 4.5, since self-polymerization'nand decomposition are accelerated if the pH is above this range, and if the pH is below this range, the. materials to be waterproofed are sometimes tenderized, asTwhen the complexes are used in waterproofing paper.

In the preparation of the preferred chromyl chloride 2,909,545 .Patented Oct. 20, 1959 sizingagents for glass cloth andas chemically. resistant coatings forLfab'rics, 'glass,.metals, and the like.

The perchlorofluoromonocarboxylic' acids which may be used in the process of thisv invention are perchlorofluoromonocarboxylic acids having from about 4 to about i 20 carbon atoms, and these acids may be prepared in a variety of ways. 'For example, they may be produced by subjecting perhalogenated aliphatic olefins having at least 7 carbon atoms and being at least half fluorinated to oxidation conditions in the presence of a vigorous oxygencontaining oxidation reagent such as free oxygen iinzthe presence of -.ultraviolet' light, free oxygen in the presence. of elementalzfluorine,andpermanganate salts in aliquid medium. Preparation of the acids'according Jtoxthis.

method-isdisclosed in copending'application, Serial No. 452,706,fi1ed August 27, 1954.

The acids may also 'be prepared, by subjecting aliphatic perhalogenated :high polymers :to thermal cracking ;con-j ditions to produce-lower molecular tweight @unsatur'ated materials having molecular weights in the oil-';or.-;Wax

. range and subjecting these materials to oxidation at a action to an oxygen-containing trivalent chromium comcomplexes, a; solution of chromyl chloride in an inert solvent is added to asolution of a reducing agent; such as an alcohol, and a perchlorofluoromonocarboxylic acid in the inert solvent. Heat is evolved during the. addition, and the reaction mixture may berefl'uxed for a period of l to 4 hours. The solution may then be evaporated,

leaving the 'solid complex. The complex may then be prepared as a solution in acetone or alcohol and the like, and this solution maybe diluted with water prior to the use of the complex as a waterproofing agent.

Preferably, the complexes are prepared under anhydrous conditionsand stored as 20 weight percent solutions in anhydrous isopropyl alcohol. These solutions are diluted with waterto form a. 1 to 5 percent by weight solution just prior to application as waterproofing agents.

A bufier, such as an' alkali metal carbonate, phosphate, citrate, acetate, formate-or' borate or "urea, is used to regulate the pH of the solution if necessary. Coated articles are usually oven dried.

In addition to being useful'as waterproofing agents for waterproofing hydrophilic substances, such as cloth,

leather, and the'like, the complexes may also be used as the formula in which Z is fliCZiTbQXYllC acid' radical ora perhalomethyl radical having a total atomic weight not in excess of 146.5 and n is an integeryfronil to -16. w'llhejpreparation of these acids is disclosed in copending application, Serial No. 452,703, filed. August 27,-1954,. and issued on Sep tember 17, 1957, as Patent No. 2,806,865 H r :The preferred process for the preparation of perchlorafluorocarboxylic acids useful in the=process of thepi'esent invention?is the hydrolysis of telorners produced by telonieri'zingzperhaloolefins using sulfuryl chloride-as 'a telogen; the preferred telomer 'being'the telom'eriza'tio n product of: chlorotrifluoroethylene and sulfuryl chloride. The hydrolyzed telomer-has the formula Z*CFC l--( CFCFC1),, Q+CF COOH v in which Z is a carboxylic acid radical or a perhalomethyl radical in which all the halogen atoms are fluorine or chlorine and n is an i'ntegerfr'om 2 to 16. The preparation ;of these acids isydisclosed in ,copending'application,

'SerialiNo.1452,705, fild August 27, 1954, and issued on September l 7,' l957,- asPatent No. 2,8-06 ;866." f'

' While certain of-the disclosures ofthefore going fedpending applications relate to the preparation of .dicar- -boxylic acidsas well as monocarboxylic acids, fonlyfthe perchlorofluoromonocarboxylic acids are used as form the chromium coordination compl x the presmpim .vention. M s

.peichlorofluoromonocarboxylic acid" is about,0.3 to 3.0

moles ofjcliromium compound er m Ie-ofmacidL inert anhydrous solvent may' be present in 'a quantity Cl(CF CFCIMCF C o .L I OhCr o EXAMPLE 1 Chromyl chloride complex of Cl(CF --CFCl) CF CO OH Chromyl chloride (0.1 mole) dissolved in 50 ml. of dichloromethane was added drop-wise to a solution of ethanol (0.055 mole) and Cl(CF CFCl) CF COOH (0.05 mole) in 100 ml. of dichloromethane. Heat was evolved during the addition, and the solution was refluxed for a period of one hour. The solution was evaporated leaving 35 grams of a deep red solid complex. An acetone solution of the complex was prepared, and samples of filter paper and cloth dipped in the solution and dried in an .oven were found to be water repellent.

EXAMPLE 2 Chromyl chloride complex of Cl(CF -CFCl) CF COOH To a stirred, refluxing solution of Cl (CF CFCl) CF CO OH (0.028 mole), isopropyl alcohol (0.054 mole) and carbon tetrachloride (125 ml.) was added drop-wise a solution of chromyl chloride (0.058, mole) in carbon tetrachloride (-45 ml.). Additional isopropyl alcohol (0.033 mole) was needed to reduce all the chromyl chloride to the Cr form (green). The resulting mixture was refluxed for one hour, cooled, and concentrated under reduced pressure. The residue (26.9 grams) was dissolved in dry isopropyl alcohol (108 grams) and filtered.

EXAMPLE 3 V Chromic nitrate complex of Cl(CF CFC1) CF CQOH A solution (pH-) of Cl(CF CFCl) CF CO0H (0.03 mole) in water (100 ml.) was diluted with a solution of Cr(NO -9H O (0.06 mole) in Water (25 ml.). The resulting mixture was heated to boiling and allowed to cool. The aqueous layer was separated by decantation. The lower organic layer was dried (24 grams), dissolved in isopropyl alcohol (96 grams) and filtered.

EXAMPLE 4"" A .Chromic acetate complex of Cl (CF CFCl) CF COOH A solution (pH-5) of Cl(CF CFCl) CF COOH 0.03

mole) in water (100 ml.) was dilutedwith a solution of we -H mole) i water ewe- 17 9 4 resulting mixture was heated to boiling, whereupon a blue-gray solid precipitated. After being allowed to cool, the solid Was filtered, dried (19.5 grams) and dissolved in isopropyl alcohol. The alcohol solution was filtered.

EXAMPLE 5 Evaluation of chrome complexes of Cl CF CFCl) CF CO OH The various chrome complexes prepared were tested for waterproofing properties. After dilution with water (some containing a neutralizing solution), filter paper was coated by dipping followed by drying in an oven at elevated temperatures. The neutralizing solution was prepared by dissolving urea (16.5 grams), sodium formate (5.0 grams) and formic acid (0.2 gram) in 78.3 ml. of water. The following table contains the data evaluating these preparations:

EVALUATION OF CHROME COMPLEXES AS WATER-' PROOFING COATINGS Volume, Neu- Chrome ml. (20% tral- Drying com solutions Water, izing pH of temp., Waterproofing plex in isoml. sol., sol. 0. properties propyl ml. alcohol) 2 98 0 3.33 120 Good. 2 96 2 4. 53 120 Poor to fair. 2 98 0 2. 84 120 Tenderized paper. 2 96 2 4. 27 120 Poor to fair. 5 95 0 2. 86 110-120 Tenderized paper. 5 95 0 2. 110-120 D0. 5 0 4. 27 -120 P001 to fair. 5 94 1 3. 78 Fair to good. 5 93 2 4. 05 120 D0. 5 92 3 4. 20 120 Do.

a Prepared from CrO,C1

Prepared from Or(NO .9H-,O.

0 Prepared from CI(OAO)3.H3O.

d A delimte precipitate appeared on dilution with water.

Of the preparative methods tried, the one involving CrO Cl appears to yield the material with the best waterproofing properties. The waterproofing properties of these preparations appear to be quite good, especially when water is allowed to drop slowly on treated material (paper or cloth). Careful control of pH is essential because a low pH 3) causes tenderization of paper and a high pH 4.5) decomposes the complex and precipitation occurs. The chrominum polymer is unaffected by acetone.

It will be obvious to those skilled in the art that many modifications may be made within the scope of the present invention without departing from the spirit thereof, and the invention includes all such modifications.

I claim:

l. Chrominum' coordination complexes selected from the group consisting of (A) the coordination complex formed by the reaction of a trivalent chromium compound which is at least one third basic with a perchlorafluoromonocarboxyh'c acid corresponding ito the formula wherein n is an integer from 1 to 9, and (B) the hydrolyzed derivatives thereof.

2. The complex of claim 1 wherein said chromium compound is formed by hydrolysis of chromic nitrate.-

3. The complex of claim 1 wherein said chromium compound is formed by hydrolysis of chromic acetate.

.4. The complex of claim 1 wherein said chromium compound is formed by-reduction of chromyl chloride in the presence of an alcohol reducing agent.

5. Chromium coordination COmplcXes selected from the group consisting of (A) the coordination complex formed by the reaction with 'one another in an inert anhydrous solvent and in the presence of an alcohol reducn g ntqf iv lent chromium compou v w iehisa f w least one third basic and a perchlorofiuoromonocarboxylic acid corresponding to the formula 7. A complex as in claim 6 wherein n is 3.

References Cited in the file of this patent UNITED STATES PATENTS Iler Oct. 10, 1950 Berry July 10, 1951 Reid Dec. 15, 1953 Olson Nov. 2, 1954 Stoops et a1. Oct. 9, 1956 

1. CHROMINUM COORDINATION COMPLEXES SELECTED FROM THE GROUP CONSISTING OF (A) THE COORDINATION COMPLEX FORMED BY THE REACTION OF A TRIVALENT CHROMIUM COMPOUND WHICH IS AT LEAST ONE THIRD BASIC WITH A PERCHLOROFLUOROMONOCARBOXYLIC ACID CORRESPONDING ITO THE FORMULA 